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SQL Anywhere 11.0.1 (Français) » SQL Anywhere Server - Database Administration » Starting and Connecting to Your Database » Working with database files


Overview of database files

Each database has the following files associated with it:

  • The database file   This file holds the database information. It typically has the extension .db.

  • The transaction log   This file holds a record of the changes made to the database, and is necessary for recovery and synchronization. It typically has the extension .log. See The transaction log.

  • The temporary file   The database server uses the temporary file to hold information needed during a database session. The database server discards this file once the database shuts down—even if the server remains running. The file has a server-generated name with the extension .tmp.The location of the temporary file can be specified when starting the database server using the -dt server option. If you do not specify the location of the temporary file when starting the database server, the following environment variables are checked, in order:

    • SATMP environment variable
    • TMP environment variable
    • TMPDIR environment variable
    • TEMP environment variable

    If none of these environment variables are defined, SQL Anywhere places its temporary file in the current directory on Windows operating systems, or in the /tmp directory on Unix.

    The database server creates, maintains, and removes the temporary file. You only need to ensure that there is enough free space available for the temporary file. You can obtain information about the space available for the temporary file using the sa_disk_free_space procedure. See sa_disk_free_space system procedure.

  • Pre-defined dbspace files   These files store your data and other files used by the database. See Pre-defined dbspaces.

Additional files

Other files can also be part of a database system, including:

  • Dbspace files   You can spread your data over several separate files, in addition to the database file. See CREATE DBSPACE statement.

    For information about dbspaces, see Using additional dbspaces.

  • Transaction log mirror files   For additional security, you can create a mirror copy of the transaction log. This file typically has the extension .mlg. See Transaction log mirrors.